Add formbuilder integration!

Adds support for an experimental javascript-based replacement for thor.

To enable it, change USE_JS_THOR to true in reason_package/settings/thor_settings.php.

This is what it looks like:
![FormBuilder Sample](https://f.cloud.github.com/assets/903181/99036/5b3656d0-6742-11e2-854d-89f5ed262cc9.png)